coincidental

adjective

co·​in·​ci·​den·​tal (ˌ)kō-ˌin(t)-sə-ˈden-tᵊl 

1

: resulting from a coincidence

a coincidental resemblance

2

: occurring or existing at the same time

coincidental deaths

Synonyms

• coetaneous
• coeval
• coexistent
• coexisting
• coextensive
• coincident
• concurrent
• contemporaneous
• contemporary
• coterminous
• simultaneous
• synchronic
• synchronous

Examples of coincidental in a Sentence

The fact that he and his boss went to the same college was purely coincidental.

the nearly coincidental deaths of Princess Diana and Mother Teresa

Recent Examples on the Web

Conventional wisdom would tell us this level of dominance was a one-time thing, a coincidental product of nearly every league member trending up at the same time. —Jim Root, New York Times, 29 Apr. 2025

Scientific studies have identified well over 400 compounds, but the idea that 420 is the definitive number is purely coincidental and not scientifically accurate. —Matt Rozo, Mercury News, 3 Apr. 2025

Their visual choices seem to be a little more than coincidental in Gibbs’ eyes. —Andre Gee, Rolling Stone, 13 Feb. 2025

The list of coincidental similarities in a class of objects goes on and on. —Phil Plait, Scientific American, 17 Apr. 2025

Word History

Etymology

coincident + -al entry 1

First Known Use

circa 1800, in the meaning defined at sense 1

Rhymes for coincidental

• developmental
• environmental
• experimental
• intersegmental
• nongovernmental
• transcontinental
• unsentimental
• accidental
• compartmental
• continental
• detrimental
• elemental

Kids Definition

coincidental

adjective

co·​in·​ci·​den·​tal (ˌ)kō-ˌin(t)-sə-ˈdent-ᵊl 

1

: resulting from a coincidence

a coincidental resemblance

2

: occurring or existing at the same time

coincidentally

-ˈdent-lē

-ᵊl-ē

adverb